A needlestick injury is a percutaneous piercing wound typically set by a needle point, but possibly also by other sharp instruments or objects. Commonly encountered by people handling needles in the medical setting, such injuries are an occupational hazard in the medical community. Occupational needlestick injuries are mainly focused on the healthcare environment, but law enforcement is at particularly high risk for incidental needlesticks, though this population is commonly overlooked. These events are of concern because of the risk to transmit blood-borne diseases through the passage of the hepatitis B virus (HBV), the hepatitis C virus (HCV), and the Human Immunodeficiency Virus (HIV), the virus that causes AIDS.

Despite their seriousness as a medical event, needlestick injuries have been neglected: most go unreported and ICD-10 coding is not available.[1] On the other hand, as needlesticks have been recognized as occupational hazards, their prevention has become the subject of regulations in an effort to reduce and eliminate this preventable event.[2]

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Needlestick injuries are a common event in the healthcare environment. When drawing blood, administering an intramuscular or intravenous drug, or performing other procedures involving sharps, the needle can slip and injure the healthcare worker. This sets the stage to transmit viruses from the source person to the recipient. These injuries also commonly occur during needle recapping and as a result of failure to place used needles in approved sharps containers. During surgery, a surgical needle may inadvertently penetrate the glove and skin of the surgeon or assistant. Penetrating accidents of the surgeon or assistant with the scalpel or other sharp instruments are also handled as a needlestick injury. Generally needlestick injuries cause only minor bleeding or visible trauma, however, even in the absence of bleeding the risk of viral infection remains. Scalpel injuries tend to be larger than a needlestick. In turn, a needlestick injury may also pose a risk for a patient if the injured health professional carries HBV, HCV or HIV. Needlestick injuries are not limited to the medical community. Any environment where sharps are encountered poses a risk.

Needlestick injuries are less frequent, yet still a serious concern among law enforcement. Eight million self-injectors generate up to three billion sharps outside formal healthcare settings in the United States every year. One-third of these sharps are produced by injection drug users of heroin, cocaine, and other illicit drugs.[3]

Injury to law enforcement officers can occur for many reasons, which include the dropping or throwing of needles in fear of arrest, use of sharps as weapons against police officers, and arrestees not declaring possession, typically during searches or pat downs.

The frequency of such events has been estimated to be about 800,000 cases in the USA alone (1999 report).[4]) Another investigation estimates the rates of injuries on a global level to affect about 3.5 million individuals.[2] Among healthcare workers nurses and physicians appear especially at risk;[5] an investigation among American surgeons indicates that almost every surgeon experienced at least one such injury during their training.[6] Within the medical field specialties differ in regard to the risk of needlestick injury, thus surgery, anesthesia, ENT, internal medicine, and dermatology tend to show relatively high, and radiology and pediatrics relatively low rates of injury.[7][8] Half or more events may go unreported as injured healthcare workers may not take the time to report, downplay the risk, or fear stigmatization and professional consequences.[1]

Needlestick injuries may occur not only with freshly contaminated sharps, but also, after some time, with needles that carry dry blood. While the infectiousness of HIV and HCV decrease within a couple of hours, HBV remains stable during desiccation and infectious for more than a week.[9]

Needlestick injuries are of significant concern to police workers. In San Diego 30% of police workers reported such injuries typically when searching suspects.[10]

A study of 1,333 police officers in the Denver Police Department found that only 43.4% of those exposed, reported their injuries. 42% of respondents indicated they were on second duty shift (evenings) when they were injured. Additionally, nearly two-thirds who experienced needlesticks indicated it was during their first five years of experience [10]

A law enforcement study in New York City Police Department identified 38.7 exposures per 10,000 police officers (includes bites & sticks), while Patrol & Narcotics officers had a 43.6/10,000 exposure rate.[11]

While needlestick injuries have the potential of transferring bacteria, protozoa, viruses and prions,[1] from a practical point the transmission of the hepatitis B and hepatitis C viruses and the human immunodeficiency virus (HIV) is important. It is estimated that annually as a consequence there are 66,000 infections with HBV, 16,000 with HCV, and 1,000 with HIV worldwide.[2] In addition, a needlestick injury may lead to significant stress and anxiety for the affected injured person. Taking care of a needlestick injury is costly, estimated to be about $2,500 in the short term in the US.[5]

Hepatitis B carries the greatest risk of transmission, with 37 to 62% of exposed workers eventually showing seroconversion and 22 to 31% showing clinical Hepatitis B infection.[12][13] The hepatitis C transmission rate has been reported at 1.8%,[12][14] but newer, larger surveys have shown only a 0.5% transmission rate.[15] The overall risk of HIV infection after percutaneous exposure to HIV-infected material in the health care setting is 0.3%.[16][17]

The specific risk of a single injury depends on a number of factors when the patients harbor the virus of concern. Injuries with a hollow-bore needle, deep penetration, visible blood on the needle, a needle that was located in a deep artery or vein, or with blood from terminally ill patients are known to increase the risk for HIV infection.[18][19]

While the vast majority of needlestick injuries occur when the source-person does not carry the HBV, HCV, and HIV and thus do not carry a risk of infection, these events nevertheless cause stress and anxiety and signal a breakdown in protocol and prevention.

Blood being drawn with a Vacutainer. A protective cap (pink) protects the needle after it is removed.

Preventive steps can be taken at several levels and include reduction or elimination of use of sharps as much as possible, engineering controls (i.e., needles or syringes with safety devices), administrative controls including training and provision of adequate resources, and work practice controls; the latter may include using instruments (not fingers) to grasp needles, load scalpels, and avoiding hand-to-hand passing of sharp instruments also preparing of medications especially removing cap. Removing cap from a needle generally causes needle stick injury. There are several ways to remove the cap from the needle but the most ideal and safest way to remove the cap is by carefully grasping the syringe and guiding the needle cap using the thumb and the pointing finger. Then gently push the cap away from the syringe to detach the cap from the hub. In this way needle stick injury can be prevented by avoiding the incidence of the rebound effect. Do not use the other hand as it increases the likeliness to have the syringe to rebound. .[5] Engineering advances include the development of safety needles and needle removers. The adherence to "no-touch" protocols that eliminate direct contact with needles in their use and disposal greatly reduce the risk of injury. In the surgical setting, especially in abdominal operations, blunt-tip suture needles are able to reduce needlestick injuries with 54%.[20][21] The American College of Surgeons (ACS) has endorsed the adoption of blunt-tip suture needles for suturing fascia.[21] In addition, the use of two pairs of gloves, double gloving, can halve the risk of needle stick injury in surgical staff.[22]

Some countries have enacted legislation to protect healthcare workers. In the US, the Needlestick Safety Act was signed in 2000 and Bloodborne Pathogens Standard in 2001. These regulations mandate the use of safety devices and needle-removers with any sharps or needles.[23] Discarded sharps enter the medical waste stream.

Syringe Exchange Programs (SEPs), also known as needle exchanges or Syringe Access Programs (SAPs), are an effective way of decreasing the risk associated with needlestick injuries. Although SEPs may not reduce the prevalence of needlesticks, the risk of exposure to blood borne pathogens is reduced. SEPs provide benefits for many parties involved. Injection Drug Users (IDUs) are a very difficult population to reach, and SEPs act as a gateway for users to other resources and provide clean needles while collecting dirty sharps. These programs keep dirty syringes off the street, and in return stop the spread of disease. SEPs also benefit law enforcement through reducing risk of exposure to disease. A study in Hartford, CT looked at syringe access and law enforcement needlestick injuries before and after laws regarding needlestick access were implemented. A study found that needlestick injury rates among Hartford police officers were lower after the new laws (six injuries in 1,007 drug-related arrests for 6-month period before new laws vs. two in 1,032 arrests for 6-month period after new laws).[24]

After a needlestick injury, certain procedures must be followed to minimize the risk of infection for the recipient. The affected area should be rinsed and washed thoroughly with soap and water; the practice to "milk out" more blood is controversial and not recommended by the CDC.[1] Lab tests of the recipient are obtained for baseline studies: HIV, acute hepatitis panel (HAV IgM, HBsAg, HB core IgM, HCV) and for immunized individuals HB surface antibody.[25] Unless already known, the infectious status of the source needs to be determined by checking for HBsAG, anti-HCV, and HIV antibody.[25] Unless the source is known to be negative for HBV, HCV, and HIV post-exposure prophylaxis (PEP) should be initiated, ideally within one hour of the injury;[8] typically this is done in the emergency department or the occupational health office. Guidelines for PEP have been updated over recent years in view of the introduction of new drugs, and protocols may differ somewhat between countries.

Current CDC guidelines call for the administration of hepatitis B immune globulin (HBIG) and/or hepatitis B vaccine. While the efficacy of the combination has not been evaluated in the needlestick injury setting, it has been shown to be the most efficacious approach in the perinatal setting. The approach has no contraindications during pregnancy and lactation.[26]

CDC guidelines acknowledge that there is no active PEP for HCV, only recommendations intended to achieve early identification of chronic disease and, when detected, referral for evaluation of treatment options. According to the CDC identification of acute infection with HCV may not necessitate active intervention.[26] However, there is some evidence that treatment with interferon alfa-2b may be beneficial preventing chronic hepatitis.[27]

CDC guidelines generally recommend a PEP protocol with 3 or more antiviral drugs, when it is known that the donor was HIV positive; however, when the viral load was low and none of the above noted risk factors are met, the CDC protocol utilizes 2 antiviral drugs. Such a 2 drug protocol should also be considered when the donor status cannot be determined (e.g. injury by a random needle in a used sharps container), but there is an increased risk that the source was from a risk group for HIV.[18] PEP drugs for prevention of HIV infection are given for 4 weeks and may include nucleoside reverse transcriptase inhibitors (NRTIs), nucleotide reverse transcriptase inhibitors (NtRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and a single fusion inhibitor. PEP anti-HIV regimens are accompanied by significant side effects and their utilization is not indicated when there is evidence that HIV transmission is not involved; also, initiated protocols can be stopped when data appear indicating that the source-person is HIV-negative. Regardless whether PEP is instituted, follow-up of exposed individuals includes counseling and HIV testing by enzyme immunoassay to monitor for a possible seroconversion for at least 6 months after exposure. Such tests are done at baseline, 6 weeks, 12 weeks, and 6 months, and longer in specific circumstances, such as co-infection with HCV.

Surveillance systems have been to track sharps injuries and the progress that is achieved in their elimination. In the US there are two voluntary national surveillance systems for tracking sharps injuries: The National Surveillance System for Health care Workers (NaSH) of the CDC[28] and EpiNet of the International Health Care Worker safety center at the University of Virginia.[29] Also, some states have set up annual surveillance reporting such as Massachusetts.[30]

^ abCenters for Disease Control and Prevention, Updated US Public Health Service guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for postexposure prophylaxis.